DSXchange

I have seen that in an odbc stage there are two update actions
1) clear table then insert rows
2)Replace existing rows completely

can anyone tell me whats the difference b/w the two?

Select each one and then examine the generated sql, the difference should be easy to spot. And 'clear' here means a 'transactional delete' of all rows in the table, as opposed to a truncate which is not transactional.